US2487472A

US2487472A - Shock absorber

Info

Publication number: US2487472A
Application number: US750902A
Authority: US
Inventors: William G Patriquin
Original assignee: Gabriel Co
Current assignee: Gabriel Co
Priority date: 1947-05-28
Filing date: 1947-05-28
Publication date: 1949-11-08
Anticipated expiration: 1966-11-08

Description

Nov. 8, 1949 w. G. PATRIQUIN 2,487,472

SHOCK ABsoRBER Filed May 28,' 1947 IN V EN TOR. MAL/fw 6. hlx/auw 1 y BY H Trae/#ng fia. 3

Patented Nov. 8, 1949 UNITED STATES OFFICE William. G'. Patri'quin, Cleveland, Ohio, assignor to The Gabriel Company; Gleveland;v Ohioi a corporation off" Ohio Application Mayv 28, isirserial No.. 750,902

(ci: 18er-ss) 5' Glaims. 14

This invention relates to ashock absorber and` particularly to a fluid' shock absorber. Although the invention isapplicable toyarious typesof fluid shock.. absorbers it is. illustrated and explained herein .byf way of example as embodied ina. direct double. actingf. tubular telescopic hydraulic shock' absorber.

An object of the inventionis. to. provide in. a uid.. shock. absorber. of` the type specified;v irnproved and novelmeansfor adjusting thev operating charactersticsioft. the. valve or valves` carried by the pistonof. thashock absorber to thus enable the shock absorber tf1-function.. properly andinthe desiredmanner.

Another objectof the: invention is to. provide a shock absorber such as referred. to` in the last named object. andVK wherein the. adjustment. of the valveor valves. carried by the:piston.-.can,be obtained withoutvdisassemblyof the shock absorber.

A further. object. of the invention is to. p rovide in. afluidr shock absorber. of the. type. having.. a pistonreciprocable ina working cylinder, means preventing thepassage of uicl from one. side.. of the piston tothe other sidethereo during.. one piston stroke until a predetermined pressure hasy been: developed. on said. one.. side. of.. the. piston whereupon said .means .functions to. al1`ow.,during the remainder. ofthe. pistonv stroke and the-existenceof said.v predetermined pressurethe passage of.` fiuidfrom said. one sidesof the'piston. tofsaid other side, thereof. and. wherein provision is-made for varying selectively-the predetermined pressure required before the iiuid canr passirom-saidi one sidetosaid other. sideo f the:- piston asaaforesaid.

Another object of: the invention is. to provide:l a shock absorber which` is.. an.V improvement: on theshock absorbers. shown, inf E. L.-. Beecher Patentsy Nos. 2,394,356issued. February.- 5', 1946, and 2,396,227, issuedzMarch 12,v 11946, in that the shiitablev packing ring carried by the pistonI and performing the dual. funotionzoii a .pistonfpacking and;` a.- valve.- is. held in: seated. position by aispring, the tension z of-. whichv can: be adjusted tto; vary vthe predetermined pressure required'-K on'. the.` impact stroke of the shockf absorber tomovei said ring; against the. action of. said spring.

A further objectf isf'to.- provide; ay shock'. absorber as providedlinzthe lastl name-d` obj ect. andwherein the4 adjustment of.x said:` spring tensionnis accomplished without; disassembling the shockrabsorber and byextendingthe cylinderv and piston rodrelative to eachother and then relatively rotatingfthe same.

A still furtherobject. is tol provide a shock absorber as specifiedlin the last-named object. and wherein the adjustment imparted to the spring tension is maintained against accidental Variance by. the force. of "the springpit'sel.'

A" still' further objfect" is to provide in a fluid shock absorber ci?" the direct" double acting tubu- Tar tel'escopingA typev the combination of means for adjusting:` the. piston carried. valves which control'. tliepassage. of fluid from one side ofthe piston tb. the otheri side. thereof 'during both impactA andi. recoil` strokes` and. whereinv the adjustments.; are.. obtainabley without; disassembling the shock absorber..

AV more. specic. object is. to. provide a shock absorber such. asf referredtov inthe last named object and-whereimthevalve which controlsthe passageof fluidkpastcr throughthe. piston on the impactfstroke can be. adjusted by relatively extendingrthe .cylinder and piston rod andthen relatively. turning. the same. While` the valve. which controls the passage 0L fluid throughor past the piston.. on. thev recoil stroke. can be. adjustedV by relativelyv collapsing the. cylinder and piston rod andtthen. relatively,l turning the same.

more general.V object of the inventionis to provide-a fluid shock absorber of the direct double acting', tubular telescopicl type. which embodies means for varying, thev operative.. characteristics of the shock absorber upon boththeimpact. and recoiLstrokesthereby furnishing a .shock absorber whiclrhas a-widerange of. utility and is adapted to provide. the.. desired, ridingy qualities for the different; vehicles on` which the. shock absorber maybemounted.

Furtherl and additional l objects and. advantages not: hereinbefore. referred. to will become apparent hereinafter during the detailed description. of an embodimentbi. theinventiontwhich isto follow.

Referring@ tof the.- accompanyingy drawingillustra-ting. said. embodiment of thef invention;

Figi. 1 isa. longitudinal-sectional view through aadirect. dcubleacting hydraulictubular telescopic shooleabsorben withzcertain of theparts including the :'pistonf. andi piston rod?. shownA in'. elevation..

Fler 2r isa; fragmentaryl partlyl elevational. and

vto the member II and eye I9.

partly sectional View on a larger scale than Fig. 1 and shows the details of the piston construction with the parts being indicated in the relationship they may assume during the impact or compression stroke of the shock absorber (the down stroke of the piston in the cylinder), the adjustment of the O-ring spring tension being indicated as maximum.

Fig. 3 is a View similar to Fig. 2 but shows the relationship which the parts may have during the recoil stroke of the shock absorber (the up stroke of the piston in the cylinder), the adjustment of the O-ring spring tension being indicated as intermediate maximum and minimum.

Fig. 4 is a detail view of the stop plate employed in the piston construction as an abutment for the coil spring which acts against the O-ring carried by the piston.

Fig. 5 is a detail View of the impact adjusting member or annulus which is interposed between the stop plate and the spring that acts on the O-ring and which member functions in cooperation with said stop plate to adjust the tension of said spring.

Figs. 6 and 7 are detail views of the, O-ring and the carrier therefor, and

Fig. 8 is an end View of the piston with the O-ring, its carrier, its spring, the impact adjusting member and the stop plate removed and is taken looking from the' top side of the piston.

A shock absorber embodying the present invention is illustrated in the drawing and is by way of example a direct double acting hydraulic tubular telescopic shock absorber. absorber comprises a substantially cylindrical casing I5 which has relative telescopic movement within a cylindrical guard housing I6 that is spaced radially outwardly from the casing I5. The upper end of the housing IB is closed by an inverted cup-shaped closure or cap member I'I provided on its outer side with an eye I8 while the piston rod I9 is operatively connected The lower end of the casing I5 is closed by a cup-shaped closure `member which has secured to its outer side a lower eye 2I. The closure members I1 and 20 extend into the housing I6 and the casing I5, respectively, and are secured thereto by welding or by other suitable means.

In mounting the shock absorber upon 'a motor vehicle similar mounting pins or trunnion rods (not shown) may be connected, respectively,V to the frame and axle of the vehicle in any suitable marmer so as to extend outwardly therefrom .in parallel relationship and pass through the eyes I8 and 2|. These pins or rods may be operatively connected within the eyes I8 and 2I by suitable means well known in the art, wherefore relative movement between the frame and axle of the vehicle will cause relative telescoping 'movement between the casing I5 and the housing I6 and relative movement of the piston rod I9 and the piston secured thereto and located in the pressure or working cylinder as will be well understood.

The pressure or working cylinder 22 of the shock absorber is disposed within the casing I5 in spaced concentric relationship therewith so that the space defined by the casing I5, cylinder 22, closure member 20 and a closure member for the upper end of the casing and cylinder, later to be referred to, constitutes a reservoir 23 for the oil or liquid or fluid in the shock absorber. The lower end of the cylinder 22 ex- This shock tends into the cup-shaped closure member 20 and is secured thereto by suitable means understood in the art. The cylinder 22 slightly upwardly of the lov/er end has secured therein a closure plate 24. The cylinder 22 below the closure plate 24 is provided with an inwardly extending bead 25 which serves to retain the closure plate in position while the cup-shaped closure member 20 is provided with a plurality of circumferentially spaced internal grooves or channels 26 which place the reservoir 23 in communication with the space between the closure plate 24 and the bottom of the cup-shaped closure member 29. The closure plate 24 is shown as provided with a fixed or constantly open orice 21 which places the working cylinder in communication with the space below the plate 24 and with the reservoir 23. It will be understood that the plate 24 may be provided, if desired or necessary, with an opening closed by a replenishing valve during the impact stroke of the shock absorber but open during the recoil stroke of the shock absorber in order to facilitate the return flow of fluid from the reservoir into the working cylinder during the recoil stroke for a purpose well understood in the art and hence not shown herein. It will also be understood that the closure plate 24 might be provided with a valve controlling the orifice 21 and openable during the impact stroke of the piston. The closure plate 24 is also provided on its inner side with spaced depressions 28 for a purpose later to be explained.

The upper end of the cylinder 22 is closed by a plug member 29 which ts into the cylinder and is suitably secured in position therein, it being noted that the upper edge of the cylinder is turned inwardly over the outer side of the plug member. The plug member 29 is provided with a central opening or bore through which slidably extends the piston rod I9. In addition the plug member 29 on its under or inner side is provided with diametrically spaced depressions 29a for a purpose later to be explained. The construction of the plug member 29 other than in the particulars `specifically referred to forms no part of the present invention and therefore further description of the same is unnecessary except to say that it tightly seals the upper end of the cylinder 22.

The upper end of the casing I5 is closed by a closure member 30 mounted in the casing and suitably connected thereto. The closure member 39 forms no part of the present invention and a detailed description thereof is unnecessary except to say that said member carries a suitable spring-pressed packing seal through which the piston rod I9 slidably extends.

The piston rod I9 at its inner end is externally threaded as indicated at 3I, see Figs. 2 and 3, while just above the threads 3l the piston rod is provided with an annular recess or groove 32. The piston comprises a body which may be formed in various ways but preferably it is a die casting. The piston body includes a lower and larger portion 33 and an upper or reduced portion 34. The periphery of the lower portion of the piston body adjacent the upper end of the said portion is spaced from the cylinder wall while the remainder of the piston portion 33 is provided with circularly spaced axially extending lands 33a slidably engaging the cylinder wall and providing between the lands grooves or channels 33h spaced from the cylinder wall. In the present illustration eight lands 33al and eight grooves or depressions 33D are shown on the periphery of the lower portion 33 of the piston body.

The lower portion 33 of the piston body is provided with a counterbore 36, the wall of which is threaded as indicated at 31 for a purpose later to be explained. The inner end of the counterbore 36, that is the upper end of the portion 33 of the -piston body, is separated from the upper reduced or smaller piston portion 34 by a wall 38 in the center of which is a bore 39 communicating with the counterbore 36 and with alarger central bore 42 formed in the upper portion 34 of the piston body. The wall 38 surrounding the bore 39 is provided with anannular recoil valve seat boss 40 projecting into the counterbo're 36 and said boss may be provided with one or more radially extending angularly spaced bleed grooves or notches 4I' for a purpose later to be explained.

The upper portion 34 of the piston body is provided with the previously referred to central bore 42 which is threaded so that the threaded end 3| of the piston rod I9 can be screwed into the bore 42 in uniting the piston body to the p-iston rod.

The upper portion 34 of the piston body is also provided radially outwardly of the bore 42 with a plurality of circularly spaced axially extending peripheral recesses or grooves 43, certain of which extend from the piston part 33 to the end of the piston part 34. The recesses 43 are substantially semi-circular'in cross section and are angularly spaced circumferentially of the piston portion 34, there being eight such recesses illustrated herein. .The recesses 43 can be die cast or otherwise formed in the piston body.

The piston portion 34 is provided with ports 44 that place the lower end of the bore 42 in communication with said certain of the recesses 43. It will be noted that in the illustration four such ports 44 are shown and hence alternate recesses 43 are in communication with the bore 42 while the remaining recesses 43 are not in communication therewith and terminate short of the piston portion 33 as indicated at 43a in Figs. 2 and 3.

A spring abutment plate or washer 45 is provided With an opening 46 similar to a bayonet slot, Wherefore the piston rod I9 can be passed through the enlarged part of said opening 46 and then the washer can be moved transversely relative tothe piston rod to bring said rod 4into the smaller part of the slot 46 with the edge of said smaller part engaging in the annular groove 32 of the piston rod and with the plate 45 engaging the end of the piston portion 34 and with said plate forming an assembly abutment for the piston body.

The large part of the bayonet slot 46 in the washer 45 overlies several of the recesses 43 and the plate is provided with a plurality of openings 41 which overlie other of the recesses 43. The upper portion 34 of the piston body is provided with one or more axially extending lugs or pins 48 which when the parts are assembled engage in openings 49 in the plate 45 and act to hold said plate against movement relative to the piston body. The plate 45 is provided with diametrically disposed segmental portions 45a, the diameter of which is substantially equal to a diameter of the piston portion 33 taken through diametrically disposed grooves 33D. Intermediate the portions 45a are diametrically disposed recessed segmental portions 45h, the radius of which is such that substantial clearance exists between the portions 45h and the cylinder wall. l

A exible packing and valve ring 50 of nor-'- mally circular cross section and formed of any suitable material such as synthetic rubber for example, is movably mounted on the upper piston portion 34 and is shown as mounted on a movable carrier 5l which isslidable on said upper portion of the piston body. The carrier 5I is in the form of `a ring of angular cross-section having an arm 5m that extends longitudinally or axially of the piston and which contacts the piston portion 34 and slides therealong and a radially extending arm which overlies the upper side of the ring 50 as viewed in the drawing. It will thus befseen that the ring 50 and the carrier 5| may move toward and away from the piston portion 33 upon changes in direction of piston movement and that when the ring 50 is in the position shown in Fig. 3 it acts not only as a piston packing but also as a valve to close the spaces between the piston portion 33 and the cylinder wall while in the position indicated in Fig. 2 said spaces are open and arein communication 'with the recesses 43 of the upper portion of the piston. The ring 5U, as stated, has thecombined function of a packing ring and a valve. `A coil spring 52 is interposed between the radial arm of the ring 5I and a spring adjustment annulus or member 53 slidable on the piston portion 34 and engaging with the abutment plate 45. The spring adjustment annulus 53 will be referred to hereinafter in greater detail as to its structure and its function. For the present it will suffice to say that the spring 52 is of such strength as to normally maintain the ring 50 seated as indicated in Fig. 3.

A cup-shaped member 54 is screwed into the counterbore 36 in the lower portion 33 of the piston body and said member has secured rigidly and centrally thereof a stud 55 which projects upwardly into the bore 39. A at disk recoil valve 56 is slidable on the stud 55 and said valve is held normally against the valve seat boss 40 by a coil spring 51 mounted on the stud 55 and contained within a small cup retainer also mounted thereon and said spring bears against the bottom of said retainer. A member 58 is mounted within thev cup-shaped member 54 and is held against said cup-shaped member by a large coil spring 53 which also acts to lock the cup-shaped member 54 in adjusted position. The member 58 has projections 58a which extend through openings in the cup-shaped member 54 and are adapted to cooperate with the recesses 28 of the closure plate 24 when the shock absorber is collapsed and the piston and cylinder relatively turned to effect an adjusting screwing in or out of. the cupshaped member 54 to vary the tension of the recoil valve spring 51 and the pressure required to unseat the recoil valve 56 during the recoil stroke of the piston.

The operation of the shock absorber as thus far described will now be explained. Assuming that the cylinder 22 is filled with suitable uid as, for instance, oil and'also that the reservoir 23 contains a suitable amount of the uid, it will be seen that the reciprocation of the piston in the cylinder takes place within such fluid. It will be assumed that the spring 52 exerts a predetermined pressure yon the ring 50 and acts to normally maintain said ring in the seated position of Fig. 3. Assuming that the piston is in its normal inactive position within the cylinder 22 and that the wheels of the vehicle upon which the shock absorber is mounted strike an obstacle and cause a compression of the vehicle springs, it will be understood that the piston moves downwardly in the cylinder spring l52 during the `iiiipai-:t stroke. 'Therefore the operating characteristics c-Ithe shock absorberontheimpactstroke can be varied to meet conditions peculiar to a particular installation.

Also by collapsing the shock absorber to engage fstheflugs 58cm the depressions :.28 :of the closure plate 2A and relatively rotatingthe cylinder and piston the tension .of the .spring 51 of the recoil valve' can be adjusted to vary the predetermined pressure required to unseatsaid valve :during :the recoil stroke v.of the piston. Hencetheoperating characteristics of thefshock absorber on the recoil stroke can be varied to meet the particular requirements of an installation Without disassembling the shock absorber.

It will thus be seen that the shock absorber embodying the present invention can have its operating characteristics for either the impact stroke or the recoil stroke or both strokes readily adjusted Without disassembly of the shock absorber,

. and cylinder and for the recoil stroke by completely collapsing the shock absorber and relatively turning the piston rod and piston.

Consequently a shock absorber embodying the present invention possesses the important advantage of being adapted for various types of installations and capable of providing a Wide range of shock absorber characteristics.

It will be noted that should the shock absorber become completely extended under a severe impact to cause the lugs to engage the plug 29 no damage will occur to said lugs since the annulus 53 can move against the spring 52 and in fact said spring 52 will act to cushion any such bottorning of the lugs 65 With respect to the plug 29.

Although a preferred embodiment of the invent-ion has been illustrated and described herein it will be understood that the invention is susceptible of Various modifications and adaptations Within the scope of the appended claims.

Having thus described my invention, I claim:

1. In a fluid shock absorber, a cylinder, a piston movable therein in opposite directions during the impact and recoil strokes and having a larger portion slidable in said cylinder and provided with peripheral passages extending from end to end of said portion, said piston having a smaller portion radially spaced from said cylinder, a resilient packing ring mounted on said smaller portion of said piston and engaging said cylinder and movable relative to said smaller portion to a passage closing position in engagement with an end of said larger portion during the recoil stroke and from said position during impact stroke, spring means acting on 'said ring to maintain it in passage closing position during the impact stroke until the :creation of a predetermined fluid pressure, means carried by said piston for adjusting said spring means to vary said required predetermined pressure to provide the desired operative characteristics of the shock absorber during its impact stroke, said adjustingpmeans including a fixed member operatively associated With the smaller portion of said piston, and a movable member carried by said smaller portion and relatively rotatable and axially movable with respect to said fixed member, said movable member engaging said spring means and being provided with camming surfaces and lands which contact said fixed member and act when said members are relatively rotated to effect relative axial movement therebetween.

2.- In a fluid `shock absorber, acylindena piston movable therein in opposite directions during theimpa-ctandrecoil strokes and Ihaving a'larger portion 'slidable in said vcylinder and provided `with peripheral Lpassa-ges Vextending from 4end to endofsaidportion, said piston hav'ingfa smaller portion-radially spaced from said-cylinder, a resilient'packing ring'mounted on said smaller portion of said piston `and engaging said cylinder and movable relative to vsaid 'smaller portion 'to a Apassage yclosing `position in engagement with an end Afoi said larger portion during the recoil stroke and `from -sa'id 'position during impact stroke, spring means acting on said ring to maintain it in passage closing position during the impact stroke until the ,creation of a predetermined uid pressure, means carried by said piston for adjusting said spring means to vary said required predetermined pressure to provide the desired operative characteristics of the shock absorber during its impact stroke, said adjusting means including a iixed member operatively associated with the smaller portion of said piston, and a movable member carried by said smaller portion and relatively rotatable and axially movable with respect to said fixed member, said xed member being in the form of a plate having at diametrically opposite points in its periphery arcuate recesses, said movable member being in the form of a flat annulus provided at diametrically opposite points adjacent its outer circumference with upstanding arcuate Walls located when the upper side of said annulus is in contact with said plate in said arcuate recesses thereof, said .walls having their upper edges in the form of rising portions and land portions which when said members are relatively rotated contact the underside of said plate and cause said members to be axially displaced relative to each other, said movable member contacting said spring means.

3. A shock absorber as defined in claim 2 and wherein said walls are provided with upstanding lugs while one end of said cylinder is provided With recesses engaging and cooperating with said lugs when said piston and cylinder are extended and relatively rotated to effect relative rotation and axial movement between said members to adjust said spring means.

44. In a uid shock absorber having a cylinder, a piston movable therein in opposite directions during the impact and recoil strokes and having a larger portion slidable in said cylinder and provided with peripheral passages extending from end to end of said portion, said piston having a smaller portion radially spaced from said cylindersa resilient packing ring mounted on said smaller portion of said piston and engaging said cylinder and movable longitudinally relative to said smaller portion to a passage closing position in engagement with an end of said larger portion during the recoil stroke and from said position during impact stroke, a member fixed with respect to said piston and located adjacent to the free end of said smaller portion, and a spring reacting against said member and said ring to maintain the latter in passage closing position during the impact stroke until the creation of a predetermined fluid pressure; the improvement which comprises an adjustable movable member on said piston and interposed between said spring and said fixed member, said members having cooperating surface means acting on relative movement between said members to adjust 1l the movable member to vary the load of said spring against said ring.

5. The improvement in a uid shock absorber as defined in claim 4 and wherein said improvement further comprises a member on said pis. ton and interposed between said spring and said Xed member and relatively rotatable and axially movable with respect to said fixed member, said members having cooperating surfaces acting upon relative rotation between. the members to move the second member axially away from the xed member and toward the larger portion of said piston and to maintain said fixed member in said axially moved position to vary the load of said spring against said ring.

WILLIAM G. PATRIQUIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 10 Number Name Date I Re. 21,908 Beecher Sept. 30, 1941 2,214,038 Beecher Sept. 10, 1940